Delay reduction method and apparatus
地域：
Shenzhen
摘要
This application discloses a delay reduction method and apparatus, applied to a random access process. The method includes: sending, by a terminal device, a message 1 to a network device, where the message 1 is a random access preamble; receiving, by the terminal device, a message 2 sent by the network device; and sending, by the terminal device, a message 3 to the network device, where a time gap between receiving the message 2 and sending the message 3 is set by the terminal based on a timing advance (TA) value. In an embodiment, the TA value is related to a message 1 format of the terminal device and a cell radius or subcarrier spacing supported by the message 1. In this solution, a TA value is reduced, and random access efficiency is improved.
說(shuō)明書(shū)
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This application is a continuation of International Application No. PCT/CN2019/080679, filed on Mar. 29, 2019, which claims priority to Chinese Patent Application No. 201810302075.3, filed on Apr. 4, 2018. The disclosures of the aforementioned applications are hereby incorporated by reference in their entireties.
This application relates to the field of communications technologies, and in particular, to a delay reduction method and apparatus.
In a random access process, a terminal sends a random access preamble (e.g., message 1, Msg1) to a base station. The base station sends a message 2 (e.g., Msg2) to the terminal in response to the random access preamble. After receiving the message 2, the terminal waits for a period of time and then sends a message 3 (e.g., Msg3) to the base station. A problem that currently needs to be resolved relates to identifying how to reduce a time gap between the second and third message (e.g., Msg2 and Msg3) to improve random access efficiency.
This application provides a delay reduction method and apparatus configured to reduce a delay in a random access process.
According to one aspect of the present disclosure, a delay reduction method is disclosed. The method is applied to a random access process and includes:
權(quán)利要求
What is claimed is:1. A delay reduction method, applied to a random access process, the method comprising:sending, by a terminal device, a message 1 to a network device, wherein the message 1 is a random access preamble; receiving, by the terminal device, a message 2 sent by the network device; and sending, by the terminal device, a message 3 to the network device, wherein a time gap between receiving the message 2 and sending the message 3 is set by the terminal based on a timing advance (TA) value, wherein: the TA value is related to a message 1 format of the terminal device and a cell radius supported by the message 1; the TA value is related to a message 1 format of the terminal device and a subcarrier spacing supported by the message 1; the TA value is related to a message 1 format of the terminal device, a cell radius supported by the message 1, and a subcarrier spacing supported by the message 1; the TA value is related to a message 1 format of the terminal device and a minimum subcarrier spacing and/or a maximum cell radius of the message 1 in a frequency range in which the terminal device operates; the TA value is determined based on a timing advance command (TAC) value indicated by the network device, wherein the TAC value is less than or equal to 3846 and is greater than or equal to a largest TAC value in TAC values of one or more terminal devices served by the network device; the TA value is determined based on a distance value indicated by the network device, wherein the distance value is less than or equal to 300 km and is greater than or equal to a largest distance value in distance values of one or more terminal devices served by the network device; or the TA value is a TA value indicated by the network device, and the TA value is less than or equal to 2 ms and is greater than or equal to a largest TA value in TA values of one or more terminal devices served by the network device. 2. The method according to claim 1 , wherein the method further comprises: receiving, by the terminal device, indication information sent by the network device, wherein the indication information is used to notify the terminal device of whether the network device uses a beam sweeping manner to receive the random access preamble. 3. The method according to claim 1 , wherein the TAC value, the TA value, or the distance value is indicated by the network device by using one or more of a physical broadcast channel (PBCH), system information (SI), remaining system information (RMSI), a system information block 1, a system information block 2, message 2 downlink control information (Msg2 DCI), a message 2 media access control header (Msg2 MAC header), and a message 2 random access response (Msg2 RAR). 4. The method according to claim 1 , wherein the TA value is further related to a scale factor indicated by the network device, and the scale factor is less than 1. 5. A delay reduction method, applied to a random access process, the method comprising:receiving, by a network device, a message 1 sent by a terminal device, wherein the message 1 is a random access preamble; sending, by the network device, a message 2 to the terminal device; and receiving, by the network device, a message 3 sent by the terminal device, wherein a time gap between receiving the message 2 and sending the message 3 is set by the terminal based on a timing advance (TA) value, wherein: the TA value is related to a message 1 format of the terminal device and a cell radius supported by the message 1; the TA value is related to a message 1 format of the terminal device and a subcarrier spacing supported by the message 1; the TA value is related to a message 1 format of the terminal device, a cell radius supported by the message 1, and a subcarrier spacing supported by the message 1; the TA value is related to a message 1 format of the terminal device and a minimum subcarrier spacing and/or a maximum cell radius of the message 1 in a frequency range in which the terminal device operates; the TA value is determined based on a timing advance command (TAC) value indicated by the network device, wherein the TAC value is less than or equal to 3846 and is greater than or equal to a largest TAC value in TAC values of one or more terminal devices served by the network device; the TA value is determined based on a distance value indicated by the network device, wherein the distance value is less than or equal to 300 km and is greater than or equal to a largest distance value in distance values of one or more terminal devices served by the network device; or the TA value is a TA value indicated by the network device, and the TA value is less than or equal to 2 ms and is greater than or equal to a largest TA value in TA values of one or more terminal devices served by the network device. 6. The method according to claim 5 , wherein the method further comprises: sending, by the network device, indication information to the terminal device, wherein the indication information is used to notify the terminal device whether the network device uses a beam sweeping manner to receive the random access preamble. 7. The method according to claim 5 , wherein the TAC value, the TA value, or the distance value is indicated by the network device by using one or more of a physical broadcast channel (PBCH), system information (SI), remaining system information (RMSI), a system information block 1, a system information block 2, message 2 downlink control information (Msg2 DCI), a message 2 media access control header (Msg2 MAC header), and a message 2 random access response (Msg2 RAR). 8. The method according to claim 5 , wherein the TA value is further related to a scale factor indicated by the network device, and the scale factor is less than 1. 9. A delay reduction apparatus, wherein the apparatus is a terminal device or a chip or module of a terminal device, and the apparatus comprises:a transmitter, configured to send a message 1 to a network device, wherein the message 1 is a random access preamble; and a receiver, configured to receive a message 2 sent by the network device, wherein the transmitter is further configured to send a message 3 to the network device, wherein a time gap between receiving the message 2 and sending the message 3 is set by the apparatus based on a timing advance (TA) value, wherein: the TA value is related to a message 1 format of the terminal device and a cell radius supported by the message 1; the TA value is related to a message 1 format of the terminal device and a subcarrier spacing supported by the message 1; the TA value is related to a message 1 format of the terminal device, a cell radius supported by the message 1, and a subcarrier spacing supported by the message 1; the TA value is related to a message 1 format of the terminal device and a minimum subcarrier spacing and/or a maximum cell radius of the message 1 in a frequency range in which the terminal device operates; the TA value is determined based on a timing advance command (TAC) value indicated by the network device, wherein the TAC value is less than or equal to 3846 and is greater than or equal to a largest TAC value in TAC values of one or more terminal devices served by the network device; the TA value is determined based on a distance value indicated by the network device, wherein the distance value is less than or equal to 300 km and is greater than or equal to a largest distance value in distance values of one or more terminal devices served by the network device; or the TA value is a TA value indicated by the network device, and the TA value is less than or equal to 2 ms and is greater than or equal to a largest TA value in TA values of one or more terminal devices served by the network device. 10. The apparatus according to claim 9 , wherein the receiver is further configured to: receive indication information sent by the network device, wherein the indication information is used to notify the terminal device of whether the network device uses a beam sweeping manner to receive the random access preamble. 11. The apparatus according to claim 9 , wherein the TAC value, the TA value, or the distance value is indicated by the network device by using one or more of a physical broadcast channel (PBCH), system information (SI), remaining system information (RMSI), a system information block 1, a system information block 2, message 2 downlink control information (Msg2 DCI), a message 2 media access control header (Msg2 MAC header), and a message 2 random access response (Msg2 RAR). 12. The apparatus according to claim 9 , wherein the TA value is further related to a scale factor indicated by the network device, and the scale factor is less than 1. 13. A delay reduction apparatus, wherein the apparatus is a network device or a chip or module of a network device, and the apparatus comprises:a receiver, configured to receive a message 1 sent by a terminal device, wherein the message 1 is a random access preamble; and a transmitter, configured to send a message 2 to the terminal device; wherein the receiver is further configured to receive a message 3 sent by the terminal device, wherein a time gap between receiving the message 2 and sending the message 3 is set by the terminal based on a timing advance (TA) value, wherein the TA value is related to a message 1 format of the terminal device and a cell radius supported by the message 1; the TA value is related to a message 1 format of the terminal device and a subcarrier spacing supported by the message 1; the TA value is related to a message 1 format of the terminal device, a cell radius supported by the message 1, and a subcarrier spacing supported by the message 1; the TA value is related to a message 1 format of the terminal device and a minimum subcarrier spacing and/or a maximum cell radius of the message 1 in a frequency range in which the terminal device operates; the TA value is determined based on a timing advance command (TAC) value indicated by the network device, wherein the TAC value is less than or equal to 3846 and is greater than or equal to a largest TAC value in TAC values of one or more terminal devices served by the network device; the TA value is determined based on a distance value indicated by the network device, wherein the distance value is less than or equal to 300 km and is greater than or equal to a largest distance value in distance values of one or more terminal devices served by the network device; or the TA value is a TA value indicated by the network device, and the TA value is less than or equal to 2 ms and is greater than or equal to a largest TA value in TA values of one or more terminal devices served by the network device. 14. The apparatus according to claim 13 , wherein the transmitter is further configured to send indication information used to indicate whether the network device uses a beam sweeping manner to receive the random access preamble to the terminal device. 15. The apparatus according to claim 13 , wherein the transmitter is further configured to send a TA scale factor to the terminal device, and the TA scale factor is less than 1. 16. The apparatus according to claim 13 , wherein the TAC value, the TA value, or the distance value is indicated by the network device by using one or more of a physical broadcast channel (PBCH), system information (SI), remaining system information (RMSI), a system information block 1, a system information block 2, message 2 downlink control information (Msg2 DCI), a message 2 media access control header (Msg2 MAC header), and a message 2 random access response (Msg2 RAR).
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